Double-shield TBM (tunnel boring machine) cross line changing construction method for geological fracture zone

Abstract

The invention discloses a geological fracture zone double-shield TBM cross line changing construction method which comprises the following steps: on the basis of detailed investigation and design investigation, drilling and coring are performed on the outer edge of a tunnel structure along the longitudinal direction of a line by adopting a geological drill, development condition data of a geological structure fracture zone are obtained, and a PVC sleeve valve pipe is pre-embedded in a drilling and coring hole site; through the pre-buried PVC sleeve valve pipe, grouting reinforcement is conducted on the tunnel broken zone in an internal and external combined mode; a jamming early warning system is carried on the TBM, torque change is monitored, and TBM tunneling parameters are selected in combination with TBM equipment propulsion parameters; special structure pipe pieces with grouting holes and multiple ribs are installed and added in time in a preceding tunnel, and the self-stability and the external force deformation resisting capacity of surrounding rock are improved through grouting; a supporting trolley system is installed in the preceding tunnel; ground surface settlement, duct piece deformation and trolley stress and deformation are monitored in a mode of combining automatic monitoring and manual monitoring. The method is high in geological fracture zone reinforcing pertinence, surrounding rock fractures are fully filled, and the reinforcing effect is good.

Description

Technical Field

[0001] The present invention relates to the technical field of TBM construction, and in particular to a double-shield TBM cross-line switching construction method in a geological fracture zone. Background Art

[0002] The subway line is affected by the adjustment of the direction of trains entering and leaving the station. It is common for the left and right lines to cross and switch lines before entering and leaving the station. The overlapping section is close in distance. During construction, the two tunnels will affect each other, repeatedly disturbing the clamped rock mass, posing a high risk to construction safety. The disturbance of the stratum by the excavation of the leading tunnel will form a loosening circle of surrounding rock, which will have an adverse effect on the excavation of the subsequent tunnel. The mechanical excavation of the subsequent tunnel will have an adverse effect on the leading tunnel, transferring the stress of the surrounding rock, forming a loosening effect, and superimposing the compressive structural load, which may cause damage to the leading tunnel structure. Especially in geological fracture zones, the pressure exerted by the TBM support shoes on the surrounding rock is directly transmitted to the leading tunnel structure, which can easily cause damage to the structure. Therefore, it is necessary to study and solve the construction problems of overlapping sections in geological fracture zones.

[0003] For example, a Chinese patent application with invention patent number CN202410289729.9 discloses a method, device, equipment, and storage medium for controlling cross-tunnel construction. The method comprises: obtaining first distance information of a tunnel intersection position from a first calibrated position of a cutterhead and second distance information of a second calibrated position of the cutterhead, respectively, to determine a cutterhead deflection angle of a target TBM; obtaining laser target guidance data of the target TBM, and determining a correction deflection angle of a drive connection of the target TBM for adjusting the excavation direction based on the laser target guidance data; and generating an excavation control signal based on the cutterhead deflection angle and the correction deflection angle. The present invention adjusts the excavation speed of the TBM in real time by detecting the cutterhead deflection angle and the correction deflection angle for adjusting the excavation direction of the TBM during the secondary start-up process of tunnel cross-tunnel construction, so that the directional deflection of the cutterhead relative to the drive connection caused by unbalanced force is kept within an allowable range, balancing cutterhead loss and construction efficiency, and improving construction quality.

[0004] For example, Chinese patent application number CN202111139252.9 discloses a rapid construction method for TBM-led dual-tunnel cross-excavation in complex strata. The method comprises the following steps: ① The main tunnel and pilot tunnel are cross-excavated by the main tunnel TBM and the pilot tunnel TBM, respectively, until the leading TBM becomes stuck when passing through a section with unfavorable geology; ② A transverse pilot tunnel is constructed at the same distance as the lagging TBM; ③ A small advance pilot tunnel is constructed within the transverse pilot tunnel toward the tunnel face of the stuck TBM; ④ Advanced active reinforcement is performed at the same distance ahead of the lagging TBM through the transverse pilot tunnel; ⑤ The trapped leading TBM is freed at the tunnel face of the stuck TBM through the small advance pilot tunnel; ⑥ The leading and lagging TBMs resume normal excavation until they pass through the section with unfavorable geology. This method features high safety, fast construction speed, and strong applicability, effectively overcoming the technical difficulties encountered in TBM freeing and advanced geological prediction.

[0005] For another example, Chinese invention patent application number CN202210643751.X discloses a confined space TBM construction method, including the following steps: Step 1: excavating a launch tunnel at one end of the tunnel along the tunnel centerline; Step 2: using advanced geological surveys to determine the surrounding rock conditions within a certain distance, dividing them into hard rock conditions and soft rock conditions. If the conditions are hard rock conditions, the distance is divided from the launch tunnel into a stress replenishment section, a buffer section, and an advance section. The stress replenishment section and the buffer section account for 1 / 100 to 3 / 100 and 1 / 20 to 3 / 20 of the distance, respectively, with the remainder being the advance section. The TBM is then pushed into the launch tunnel and construction begins. If the conditions are soft rock conditions, the distance is divided from the launch tunnel into a staggered steady section and an advance section. As the TBM advances, the segment installation and grouting of the segment area are carried out simultaneously until the entire distance is completed. This invention meets the requirements of both soft soil layers and ultra-hard rock layers.

[0006] The above-mentioned prior art discloses a cross-cavity construction control method, device, equipment and storage medium, but does not provide a solution for the construction of overlapping tunnels in geological fracture zones. Based on the above-mentioned technical problems existing in the prior art, the present invention provides a double-shield TBM cross-line switching construction method in geological fracture zones. Summary of the Invention

[0007] In order to solve the above technical problems existing in the prior art, the present invention provides a double-shield TBM cross-line construction method in a geological fracture zone.

[0008] The present invention adopts the following technical solutions: The present invention provides a double-shield TBM cross-line construction method in a geologically fractured zone, comprising: Step 1: Based on detailed survey and design, drill and core the tunnel structure along the longitudinal direction of the route using a geological drill to obtain data on the development of the geological fracture zone. PVC sleeve valve pipes are pre-buried in the core drilling holes. At the same time, other grouting holes are arranged in a plum blossom pattern and PVC sleeve valve pipes are installed. Step 2: Grouting reinforcement of the tunnel fracture zone through the pre-buried PVC sleeve valve pipe; Step 3: Based on data on the development of geological structural fracture zones, when the TBM is tunneling through rock with well-developed joints and fissures or fault fracture zones, intelligent TBM tunneling techniques are used. A jam warning system is installed on the TBM. The system monitors torque changes and combines these with TBM propulsion parameters to select TBM tunneling parameters. Step 4: Install the special structure segments in the tunnel in time, and embed the grouting hole casings when prefabricating the segments; Step 5: Install a support system consisting of multiple trolleys in the pilot tunnel. Each trolley is equipped with hydraulic support shoes to provide single-point support. Step 6: In the cross-line switching and overlapping section, a combination of automated monitoring and manual monitoring is used to monitor surface settlement, segment structure deformation, and trolley stress and deformation. When the monitoring value reaches 70% to 100% of the control value, a graded warning is triggered.

[0009] Furthermore, in step 1, a geological drill is used to drill and core the outer edge of the tunnel structure along the longitudinal direction of the route to obtain data on the development status of the geological structure fracture zone, and a PVC sleeve valve pipe is pre-buried in the drilling and core hole position, including: Step 11: Along the longitudinal direction of the line, within the range of 0.5m to 1m from the outer edge of the tunnel structure, alternately arrange supplementary exploration holes with a longitudinal spacing of 10m to 15m. The drilling holes are drilled with geological drills to a depth of 1.5m to 3m below the tunnel bottom. Step 12: Determine the joint development of the geological structural fracture zone based on the integrity of the core sampling rock column, measure the groundwater rise rate, calculate the water inflow volume of the structural fracture zone, and determine the probability of water and sand inflow; Step 13: At the same time, a PVC sleeve valve pipe is pre-buried in the core drilling hole to serve as a grouting hole for grouting reinforcement of the broken zone in the next step.

[0010] Furthermore, in step 2, grouting reinforcement is performed on the tunnel fracture zone through the pre-buried PVC sleeve valve pipe, including: Step 21, preferably using surface grouting to reinforce the tunnel fracture zone; Step 22: When the tunnel is buried deep, use advance grouting pre-reinforcement in the tunnel and special segment lateral grouting pre-reinforcement.

[0011] Furthermore, in step 21, the surface grouting method is preferably used to reinforce the broken zone of the tunnel, including: In step 211, the surface grouting is performed using a drilling and grouting machine for hole drilling and grouting, and the grouting method is a forward grouting method; the grouting holes are arranged in a plum blossom pattern, with a hole spacing of 1.5m and a hole depth of 1.5m below the tunnel bottom. The grouting pressure is 0.5Mpa~1.5Mpa, and the grouting slurry is pure cement slurry with a cement-water ratio of 0.8~1:1.

[0012] Furthermore, when the tunnel is buried deep in step 22, the pre-reinforcement method of in-hole advance grouting and special segment lateral grouting is adopted, including: Step 221: The advance tunnel uses the TBM's own advanced drilling rig and grouting equipment to perform advance grouting on the broken surrounding rock in front of the excavation face. After the holes are drilled, they are cleaned with high-pressure water to prevent grouting and leakage. The grouting principle and sequence are symmetrical grouting from both sides toward the vault, with a grouting pressure of 0.8-2 MPa. The grouting is terminated by dual control of grouting volume and grouting pressure, using cement-water glass dual-liquid grouting. Step 222: When the rock is particularly broken, use small guide tubes for advance support. The circumferential spacing of the small guide tubes is 0.4 m, the length is less than 15 m, and the external insertion angle is not more than 5° in principle to avoid affecting the TBM mechanical excavation. Step 223: The subsequent tunnel uses the special segments of the preceding tunnel and performs lateral advance grouting for pre-reinforcement. The reinforcement content of the special segments is increased by 40kg / m compared to the ordinary segments. 3 In addition to the hoisting holes, each segment has 4 more grouting holes, and the grouting hole casings are prefabricated and embedded in the segment. Step 224: After the first tunnel is passed, during the second grouting, a drilling rig is used to drill holes for deep hole grouting. The hole depth penetrates the outer edge of the rear tunnel by no less than 1 meter. A PVC sleeve valve pipe is installed. The grouting pressure is 0.5~1Mpa. The grouting slurry uses pure cement slurry or cement-water glass double liquid slurry. The grouting sequence is from bottom to top and from back to front longitudinally to ensure that the slurry fills the surrounding rock cracks of the entire section of the rear tunnel.

[0013] Furthermore, in step 3, based on the geological structural fracture zone development data, when the TBM is excavating through a rock with relatively developed joints and fissures or a fault fracture zone, intelligent TBM excavation methods are used, and a jam warning system is installed on the TBM. The jam warning system monitors torque changes and combines the TBM equipment propulsion parameters to select TBM excavation parameters, including: Step 31, tunneling is performed in an automatic torque control mode or a manual control mode; Step 32: When tunneling in the automatic torque control mode, the tunneling penetration is 15-30 mm, the torque value is 60-75% of the rated value, the cutterhead speed is 2-4 r / min, and the thrust is 40%-60% of the rated value, 5000-7000 kN. Step 33: When tunneling in manual control mode, the thrust is 50% to 70% of the rated value, 6000 to 8000 kN, the tunneling penetration is 10 to 20 mm, the torque is 50 to 60% of the rated value, and the variation range is less than or equal to 10%, and the cutterhead speed is 1 to 3 r / min; Step 34: During the excavation process, if it is found that the proportion of rocks with a diameter of 30 cm reaches more than 20%, the excavation speed should be reduced, the penetration depth should not exceed 5 mm, the torque variation range should not exceed 10%, and the advancement speed should be less than 60% of the preset value, so as to steadily cross the broken zone.

[0014] Furthermore, the special structure segments are promptly installed in the advance tunnel described in step 4, and the grouting hole casings are pre-buried during the prefabrication of the segments, including: Step 41: For the special segment structure, excluding the capping block, each segment is provided with four grouting holes in addition to the hoisting holes. The grouting hole casings are prefabricated simultaneously with the segment, and the circumferential spacing of the grouting holes is 1 / 3 to 1 / 2 of the segment width. Among them, the special segment structure is a segment with 40kg / m³ more reinforcement than the ordinary segment and 4 more grouting holes; Step 42: In the leading tunnel, special structural segments are used to perform lateral grouting pre-reinforcement treatment on the surrounding rock between the two tunnels and the cracks in the surrounding rock of the trailing tunnel; Step 43: When the two lines are switched, special pipe segments are installed in the adjacent leading tunnel to resist the deformation caused by the excavation thrust and the squeezing pressure of the horizontal support shoes during the excavation of the following tunnel, ensure the forming quality of the leading tunnel, and be able to resist the deformation of the leading tunnel caused by the permanent dynamic load of train operation in the following tunnel during the operation period; use the additional grouting casing to drill grouting holes and grouting reinforcement to the following tunnel and the cracks of the clamping rock pillars to ensure the stability of the excavation posture of the following tunnel and prevent rock blocks from falling and getting stuck in the shield.

[0015] Furthermore, in step 5, a support system consisting of multiple trolleys is installed in the pilot tunnel, each trolley being provided with a hydraulic support shoe to provide single-point support force, including: Step 51: The entire support system is composed of multiple trolleys. The trolley structural components include the trolley gantry, walking beam, support shoes, hydraulic system, and electronic control system. The material of the trolley components is not less than Q335, and the connecting bolts between components are not less than 10.9 grade. The welds are all groove welded and tested for flaw detection. The main beam of the walking beam is made of steel, and the remaining components are welded with 20 mm thick steel plates. Step 52: Each trolley consists of three horseshoe-shaped gantries. The distance between each gantries is the same as the width of the pipe segment. The inner diameter of the horseshoe-shaped gantries meets the clearance requirements for the slag train. The outer side is polygonal. Five hydraulic support shoes are set on the outer edge of each gantries. Each support shoe provides a support force of not less than 45 tons. A set of running wheels is installed under the walking beams of the front and rear gantries of each trolley. The middle gantries are configured with adjustable screw top supports. Step 53: Install a self-locking hydraulic cylinder and a polyurethane steel box on each support shoe. The cylinder has a diameter of 150 mm and a stroke of 300 mm. A pressure sensor is also installed. The polyurethane steel box has a thickness of 200 mm and a width of 150 mm. Step 54 : The support shoe is powered by two hydraulic pump stations with a flow rate of not less than 10 L / min and a system pressure of 25 MPa. Step 55 , the electronic control system is an integrated touch screen control panel, which controls the extension and retraction of each support shoe cylinder and simultaneously realizes the linkage of the extension and retraction of the entire group of cylinders.

[0016] Furthermore, in the crossing and overlapping section described in step 6, a combination of automated and manual monitoring is used to monitor ground settlement, segment deformation, and trolley stress and deformation. When the monitored value reaches 70% to 100% of the control value, a graded warning is triggered, including: Step 61: Surface settlement monitoring points are arranged every 10 m along the axis, with a monitoring longitudinal section spacing of 20 m to 50 m. A total of 7 sections are arranged, with 9 points arranged transversely in each section, with a spacing of 3 m to 10 m. Step 62: The interval between the segment deformation monitoring points in the tunnel is 5 m, with 3 monitoring points in each section, 1 vault settlement monitoring point, and 1 set of convergence monitoring points. Step 63: The support trolley stress monitoring points are located at the head and tail of the preceding tunnel support reinforcement trolley. Two sections are arranged, and three measuring points are arranged on each section. They are located on the left and right sides and the top of the support trolley to automatically monitor radial forces. The stress measuring points use surface strain gauges welded to the support structure of the support trolley. The support trolley deformation measuring points are arranged synchronously with the support trolley stress monitoring point sections. Three measuring points are arranged on each section. They are located on the left and right sides and the top of the support trolley. Step 64: Annular stress monitoring points are arranged in sections of the tunnel segment structure simultaneously with the deformation sections of the support trolley. Two monitoring points are arranged on each section, located on both sides of the segment. The segment stress monitoring system moves forward with the support reinforcement trolley until the overlap section ends. The movable trolley support position is matched to the subsequent tunneling speed of the TBM. Step 65: The monitoring cycle begins with the installation of the support trolley. Each monitoring section monitoring cycle is repeated as the support trolley of the preceding tunnel advances forward until the TBM assembly ring of the succeeding tunnel leaves the overlapping parallel terminal mileage. Step 66: During the monitoring period, the ground settlement, segment settlement and convergence, and trolley deformation are monitored twice a day. The support trolley and segment stress monitoring uses automated real-time monitoring to collect data. Step 67: The surface settlement change rate is ±3 mm / d, and the cumulative value is ±30 mm; the clearance convergence change rate is ±3 mm / d, and the cumulative value is ±0.2%D, where D is the tunnel diameter; the structural crown sinking change rate is ±2 mm / d, and the cumulative value is ±20 mm; the trolley structure deformation control value is 10 mm; Step 68: When the monitoring value reaches 70% of the control value, a yellow warning occurs; when it reaches 85% of the control value, an orange warning occurs; and when it reaches 100% of the control value, a red warning occurs.

[0017] Compared with the prior art, the present invention has the following advantages: 1. The double-shield TBM cross-line replacement construction method for geologically fractured zones described in the present invention is highly targeted in reinforcing geologically fractured zones. It adopts a combined internal and external reinforcement method, fully fills the surrounding rock cracks, and has a good reinforcement effect. It plays a positive role in controlling the TBM mechanical excavation posture and preventing shield "stuck".

[0018] 2. The double-shield TBM cross-line replacement construction method for geological fracture zones described in the present invention improves the deformation capacity of the TBM segments in resisting external forces by installing a special type of segment. At the same time, it changes the grouting method of the surrounding rock of the subsequent tunnel, enhances the grouting effect of the subsequent tunnel, and improves the stability of the surrounding rock. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of a double-shield TBM cross-line switching construction method in a geological fracture zone according to an embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific implementation methods. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other unless there is a conflict. Example

[0021] like Figure 1 As shown, the double-shield TBM cross-line switching construction method in a geologically fractured zone includes: Step 1: Based on detailed survey and design, drill and core the tunnel structure along the longitudinal direction of the route using a geological drill to obtain data on the development of the geological fracture zone. PVC sleeve valve pipes are pre-buried in the core drilling holes. At the same time, other grouting holes are arranged in a plum blossom pattern and PVC sleeve valve pipes are installed. Step 2: Grouting reinforcement of the tunnel fracture zone through the pre-buried PVC sleeve valve pipe; Step 3: Based on data on the development of geological structural fracture zones, when the TBM is tunneling through rock with well-developed joints and fissures or fault fracture zones, intelligent TBM tunneling techniques are used. A jam warning system is installed on the TBM. The system monitors torque changes and combines these with TBM propulsion parameters to select TBM tunneling parameters. Step 4: Install the special structure segments in the tunnel in time, and embed the grouting hole casings when prefabricating the segments; Step 5: Install a support system consisting of multiple trolleys in the pilot tunnel. Each trolley is equipped with hydraulic support shoes to provide single-point support. Step 6: In the cross-line switching and overlapping section, a combination of automated monitoring and manual monitoring is used to monitor surface settlement, segment structure deformation, and trolley stress and deformation. When the monitoring value reaches 70% to 100% of the control value, a graded warning is triggered.

[0022] Furthermore, in step 1, a geological drill is used to drill and core the outer edge of the tunnel structure along the longitudinal direction of the route to obtain data on the development status of the geological structure fracture zone, and a PVC sleeve valve pipe is pre-buried in the drilling and core hole position, including: Step 11: Along the longitudinal direction of the line, within the range of 0.5m to 1m from the outer edge of the tunnel structure, alternately arrange supplementary exploration holes with a longitudinal spacing of 10m to 15m. The drilling holes are drilled with geological drills to a depth of 1.5m to 3m below the tunnel bottom. Step 12: Determine the joint development of the geological structural fracture zone based on the integrity of the core sampling rock column, measure the groundwater rise rate, calculate the water inflow volume of the structural fracture zone, and determine the probability of water and sand inflow; Step 13: At the same time, a PVC sleeve valve pipe is pre-buried in the core drilling hole to serve as a grouting hole for grouting reinforcement of the broken zone in the next step.

[0023] Furthermore, in step 2, grouting reinforcement is performed on the tunnel fracture zone through the pre-buried PVC sleeve valve pipe, including: Step 21, preferably using surface grouting to reinforce the tunnel fracture zone; Step 22: When the tunnel is buried deep, use advance grouting pre-reinforcement in the tunnel and special segment lateral grouting pre-reinforcement.

[0024] Furthermore, in step 21, the surface grouting method is preferably used to reinforce the broken zone of the tunnel, including: In step 211, the surface grouting is performed using a drilling and grouting machine for hole drilling and grouting, and the grouting method is a forward grouting method; the grouting holes are arranged in a plum blossom pattern, with a hole spacing of 1.5m and a hole depth of 1.5m below the tunnel bottom. The grouting pressure is 0.5Mpa~1.5Mpa, and the grouting slurry is pure cement slurry with a cement-water ratio of 0.8~1:1.

[0025] Furthermore, when the tunnel is buried deep in step 22, the pre-reinforcement method of in-hole advance grouting and special segment lateral grouting is adopted, including: Step 221: The advance tunnel uses the TBM's own advanced drilling rig and grouting equipment to perform advance grouting on the broken surrounding rock in front of the excavation face. After the holes are drilled, they are cleaned with high-pressure water to prevent grouting and leakage. The grouting principle and sequence are symmetrical grouting from both sides toward the vault, with a grouting pressure of 0.8-2 MPa. The grouting is terminated by dual control of grouting volume and grouting pressure, using cement-water glass dual-liquid grouting. Step 222: When the rock is particularly broken, use small guide tubes for advance support. The circumferential spacing of the small guide tubes is 0.4 cm, the length is less than 15 m, and the external insertion angle is not more than 5° in principle to ensure TBM mechanical excavation. Step 223: The subsequent tunnel uses the special segments of the preceding tunnel and performs lateral advance grouting for pre-reinforcement. The reinforcement content of the special segments is increased by 40kg / m compared to the ordinary segments. 3 In addition to the hoisting holes, each segment has 4 more grouting holes, and the grouting hole casings are prefabricated and embedded in the segment. Step 224: After the first tunnel is passed, during the second grouting, a drilling rig is used to drill holes for deep hole grouting. The hole depth penetrates the outer edge of the rear tunnel by no less than 1 meter. A PVC sleeve valve pipe is installed. The grouting pressure is 0.5~1Mpa. The grouting slurry uses pure cement slurry or cement-water glass double liquid slurry. The grouting sequence is from bottom to top and from back to front longitudinally to ensure that the slurry fills the surrounding rock cracks of the entire section of the rear tunnel.

[0026] Furthermore, in step 3, based on the geological structural fracture zone development data, when the TBM is excavating through a rock with relatively developed joints and fissures or a fault fracture zone, intelligent TBM excavation methods are used, and a jam warning system is installed on the TBM. The jam warning system monitors torque changes and combines the TBM equipment propulsion parameters to select TBM excavation parameters, including: Step 31, tunneling is performed in an automatic torque control mode or a manual control mode; Step 32: When tunneling in the automatic torque control mode, the tunneling penetration is 15-30 mm, the torque value is 60-75% of the rated value, the cutterhead speed is 2-4 r / min, and the thrust is 40%-60% of the rated value, 5000-7000 kN. Step 33: When tunneling in manual control mode, the thrust is 50% to 70% of the rated value, 6000 to 8000 kN, the tunneling penetration is 10 to 20 mm, the torque is 50 to 60% of the rated value, and the variation range is less than or equal to 10%, and the cutterhead speed is 1 to 3 r / min; Step 34: During the excavation process, if it is found that the proportion of rocks with a diameter of 30 cm reaches more than 20%, the excavation speed should be reduced, the penetration depth should not exceed 5 mm, the torque variation range should not exceed 10%, and the advancement speed should be less than 60% of the preset value, so as to steadily cross the broken zone.

[0027] Furthermore, the special structure segments are promptly installed in the advance tunnel described in step 4, and the grouting hole casings are pre-buried during the prefabrication of the segments, including: Step 41: For the special segment structure, excluding the capping block, each segment is provided with four grouting holes in addition to the hoisting holes. The grouting hole casings are prefabricated simultaneously with the segment, and the circumferential spacing of the grouting holes is 1 / 3 to 1 / 2 of the segment width. Among them, the special segment structure is a segment with 40kg / m³ more reinforcement than the ordinary segment and 4 more grouting holes; Step 42: In the leading tunnel, special structural segments are used to perform lateral grouting pre-reinforcement treatment on the surrounding rock between the two tunnels and the cracks in the surrounding rock of the trailing tunnel; Step 43: When the two lines are changing, special segments are installed in the adjacent leading tunnel to resist deformation caused by the thrust of the excavation and the squeezing force of the horizontal support shoes during the excavation of the following tunnel. This ensures the forming quality of the leading tunnel and can resist deformation of the leading tunnel caused by the permanent dynamic load of train operation in the following tunnel during the operation period. Utilize the added grouting casing, drill grouting holes, and carry out grouting reinforcement on the subsequent tunnel and the cracks of the clamping rock pillars to ensure the stability of the excavation posture of the subsequent tunnel and prevent rock blocks from falling and jamming the shield.

[0028] Furthermore, in step 5, a support system consisting of multiple trolleys is installed in the pilot tunnel. Each trolley is equipped with hydraulic grippers to provide sufficient single-point support force. The support force provided varies depending on the equipment model, including: Step 51: The entire support system is composed of multiple trolleys. The trolley structural components include the trolley gantry, walking beam, support shoes, hydraulic system, and electronic control system. The material of the trolley components is not less than Q335, and the connecting bolts between components are not less than 10.9 grade. The welds are all groove welded and tested for flaw detection. The main beam of the walking beam is made of steel, such as H400x300 steel, and the remaining components are all welded with 20mm thick steel plates. Step 52: Each trolley consists of three horseshoe-shaped gantries. The distance between each gantries is the same as the width of the pipe segment. The inner diameter of the horseshoe-shaped gantries meets the clearance requirements for the slag train. The outer side is polygonal. Five hydraulic support shoes are set on the outer edge of each gantries. Each support shoe provides a support force of not less than 45 tons. A set of running wheels is installed under the walking beams of the front and rear gantries of each trolley. The middle gantries are configured with adjustable screw top supports. Step 53: Install a self-locking hydraulic cylinder and a polyurethane steel box on each support shoe. The cylinder has a diameter of 150 mm and a stroke of 300 mm. A pressure sensor is also installed. The polyurethane steel box has a thickness of 200 mm and a width of 150 mm. Step 54 : The support shoe is powered by two hydraulic pump stations with a flow rate of not less than 10 L / min and a system pressure of 25 MPa. Step 55: The electronic control system is an integrated touch screen control panel, which controls the extension and retraction of each support shoe cylinder and simultaneously realizes the linkage of the extension and retraction of the entire group of cylinders: During assembly, each trolley section is connected by a tie rod to form an integral trolley. Each trolley section is assembled on the ground. During assembly, the main beam of the walking beam and the walking wheels and top support screws below it are first installed on the ground. The horseshoe-shaped gantry is installed above the walking beam in sequence. The support shoe base is installed on the outer edge of the gantry in sequence. The support shoe is then installed on the base. The support cylinder pipeline is connected, and the trolley connecting rod is installed. After lowering into the well, the connecting rod is used to connect each trolley section. After assembly is completed, each trolley section is lifted into the well with a gantry crane. After being lowered into the well, the trolley frame is placed on a dump truck and towed to the installation site with an electric car to be assembled into an integral trolley; the trolley travel track is installed at the installation site, and an electric hoist is installed on the lifting hole on the top of the pipe segment. After each trolley section is transported to the installation site, three gantries are lifted with an electric hoist, and the electric car drives the dump truck to leave the installation site. The trolley is slowly and evenly lowered onto the travel track, and each trolley section is connected with a connecting rod to form an integral trolley. The internal and external difference of the curve is adjusted by connecting the pull rod and the screw rod; finally, the hydraulic pump station and the electrical control cabinet are installed on the walking beam, the hydraulic oil pipeline is connected, the hydraulic station solenoid valve is installed, the control cabinet electrical circuit is connected, and the control cabinet buttons are marked.

[0029] Trolley debugging: First debug a single cylinder of the hydraulic pump station, mainly to check whether the hydraulic station valve group, hydraulic station leakage, cylinder extension and contraction, oil pipeline leakage, cylinder lifting length and cylinder ejection pressure are normal. If there is no abnormality, conduct multiple groups of joint debugging to check equipment trial operation, pressure characteristic test, pressure resistance test, leakage test and stroke test, and check whether the cylinder group is coordinated.

[0030] Trolley Operation: Before the arrival of the TBM in the trailing tunnel, all the trolley support shoes are placed on the tunnel segments. Once the required support pressure is reached, the TBM begins excavation. When the TBM approaches the threshold of the tunnel thrust, excavation is halted, all the trolley support shoes are retracted, the top support screw under the walking beam is rotated, and the entire trolley is towed by a battery-powered vehicle to the next cycle. Each cycle step does not exceed the length of the TBM shield. After supporting the leading tunnel segments again, the TBM continues excavation in the trailing tunnel. This cycle repeats until the trailing tunnel passes the threshold, and the trolley is disassembled. After each movement, the rear end of the trolley is within 3 meters of the rear end of the TBM (12.5m long). Each TBM excavation length does not exceed 6m. Excavation can only resume after the trolley is moved.

[0031] Furthermore, in the crossing and overlapping section described in step 6, a combination of automated and manual monitoring is used to monitor ground settlement, segment deformation, and trolley stress and deformation. When the monitored value reaches 70% to 100% of the control value, a graded warning is triggered, including: Step 61: Surface settlement monitoring points are arranged every 10 m along the axis, with a monitoring longitudinal section spacing of 20 m to 50 m. A total of 7 sections are arranged, with 9 points arranged transversely in each section, with a spacing of 3 m to 10 m. Step 62: The interval between the segment deformation monitoring points in the tunnel is 5 m, with 3 monitoring points in each section, 1 vault settlement monitoring point, and 1 set of convergence monitoring points. Step 63: The support trolley stress monitoring points are located at the head and tail of the preceding tunnel support reinforcement trolley. Two sections are arranged, and three measuring points are arranged on each section. They are located on the left and right sides and the top of the support trolley to automatically monitor radial forces. The stress measuring points use surface strain gauges welded to the support structure of the support trolley. The support trolley deformation measuring points are arranged synchronously with the support trolley stress monitoring point sections. Three measuring points are arranged on each section. They are located on the left and right sides and the top of the support trolley. Step 64: Annular stress monitoring points are arranged in sections of the tunnel segment structure simultaneously with the deformation sections of the support trolley. Two monitoring points are arranged on each section, located on both sides of the segment. The segment stress monitoring system moves forward with the support reinforcement trolley until the overlap section ends. The movable trolley support position is matched to the subsequent tunneling speed of the TBM. Step 65: The monitoring cycle begins with the installation of the support trolley. Each monitoring section monitoring cycle is repeated as the support trolley of the preceding tunnel advances forward until the TBM assembly ring of the succeeding tunnel leaves the overlapping parallel terminal mileage. Step 66: During the monitoring period, the ground settlement, segment settlement and convergence, and trolley deformation are monitored twice a day. The support trolley and segment stress monitoring uses automated real-time monitoring to collect data. Step 67: The surface settlement change rate is ±3 mm / d, and the cumulative value is ±30 mm; the clearance convergence change rate is ±3 mm / d, and the cumulative value is ±0.2%D, where D is the tunnel diameter; the structural crown sinking change rate is ±2 mm / d, and the cumulative value is ±20 mm; the trolley structure deformation control value is 10 mm; Step 68: When the monitoring value reaches 70% of the control value, a yellow warning occurs; when it reaches 85% of the control value, an orange warning occurs; and when it reaches 100% of the control value, a red warning occurs.

[0032] The present invention is not limited to the above-described embodiments. The above-described embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims.

Claims

1. A double-shield TBM cross-line construction method in a geological fracture zone, characterized in that: include: Step 1: Based on detailed survey and design, drill and core the tunnel structure along the longitudinal direction of the route using a geological drill to obtain data on the development of the geological fracture zone. PVC sleeve valve pipes are pre-buried in the core drilling holes. At the same time, other grouting holes are arranged in a plum blossom pattern and PVC sleeve valve pipes are installed. Step 2: Grouting reinforcement of the tunnel fracture zone through the pre-buried PVC sleeve valve pipe; Step 3: Based on data on the development of geological structural fracture zones, when the TBM is tunneling through rock with well-developed joints and fissures or fault fracture zones, intelligent TBM tunneling techniques are used. A jam warning system is installed on the TBM. The system monitors torque changes and combines these with TBM propulsion parameters to select TBM tunneling parameters. Step 4: Install the special structure segments in the tunnel in time, and embed the grouting hole casings when prefabricating the segments; Step 5: Install a support system consisting of multiple trolleys in the pilot tunnel. Each trolley is equipped with hydraulic support shoes to provide single-point support. Step 6: In the cross-line switching and overlapping section, a combination of automated monitoring and manual monitoring is used to monitor surface settlement, segment structure deformation, and trolley stress and deformation. When the monitoring value reaches 70% to 100% of the control value, a graded warning is triggered.

2. A double-shield TBM cross-line construction method for a geological fracture zone according to claim 1, characterized in that: In step 1, drill and core the outer edge of the tunnel structure along the longitudinal direction of the route using a geological drill to obtain data on the development of the geological structural fracture zone, and pre-embed PVC sleeve valve pipes in the core drilling holes, including: Step 11: Along the longitudinal direction of the line, within the range of 0.5m to 1m from the outer edge of the tunnel structure, alternately arrange supplementary exploration holes with a longitudinal spacing of 10m to 15m. The drilling holes are drilled with geological drills to a depth of 1.5m to 3m below the tunnel bottom. Step 12: Determine the joint development of the geological structural fracture zone based on the integrity of the core sampling rock column, measure the groundwater rise rate, calculate the water inflow volume of the structural fracture zone, and determine the probability of water and sand inflow; Step 13: At the same time, a PVC sleeve valve pipe is pre-buried in the core drilling hole to serve as a grouting hole for grouting reinforcement of the broken zone in the next step.

3. The double-shield TBM cross-line construction method for a geological fracture zone according to claim 1 is characterized in that: Step 2, through the pre-buried PVC sleeve valve pipe, grouting reinforcement is carried out on the tunnel fracture zone, including: Step 21, preferably using surface grouting to reinforce the tunnel fracture zone; Step 22: When the tunnel is buried deep, use advance grouting pre-reinforcement in the tunnel and special segment lateral grouting pre-reinforcement.

4. A double-shield TBM cross-line construction method for geological fracture zones according to claim 3, characterized in that: Step 21 preferably uses surface grouting to reinforce the tunnel fracture zone, including: In step 211, the surface grouting is performed using a drilling and grouting machine for hole drilling and grouting, and the grouting method is a forward grouting method; the grouting holes are arranged in a plum blossom pattern, with a hole spacing of 1.5m and a hole depth of 1.5m below the tunnel bottom. The grouting pressure is 0.5Mpa~1.5Mpa, and the grouting slurry is pure cement slurry with a cement-water ratio of 0.8~1:

1.

5. The double-shield TBM cross-line construction method in a geological fracture zone according to claim 3 is characterized in that: When the tunnel is buried deep as described in step 22, the pre-reinforcement method of in-hole advance grouting and special segment lateral grouting is adopted, including: Step 221: The advance tunnel uses the TBM's own advanced drilling rig and grouting equipment to perform advance grouting on the broken surrounding rock in front of the excavation face. After the holes are drilled, they are cleaned with high-pressure water to prevent grouting and leakage. The grouting principle and sequence are symmetrical grouting from both sides toward the vault, with a grouting pressure of 0.8-2 MPa. The grouting is terminated by dual control of grouting volume and grouting pressure, using cement-water glass dual-liquid grouting. Step 222: When the rock is particularly broken, use small pipes for advance support. The circumferential spacing of the small pipes is 0.4 m, the length is less than 15 m, and the external insertion angle is within 5° to ensure TBM mechanical excavation. Step 223: The subsequent tunnel uses the special segments of the preceding tunnel and performs lateral advance grouting for pre-reinforcement. The reinforcement content of the special segments is increased by 40kg / m compared to the ordinary segments. 3 In addition to the hoisting holes, each segment has 4 more grouting holes, and the grouting hole casings are prefabricated and embedded in the segment. Step 224: After the first tunnel is passed, during the second grouting, a drilling rig is used to drill holes for deep hole grouting. The hole depth penetrates the outer edge of the rear tunnel by no less than 1 meter. A PVC sleeve valve pipe is installed. The grouting pressure is 0.5~1Mpa. The grouting slurry uses pure cement slurry or cement-water glass double liquid slurry. The grouting sequence is from bottom to top and from back to front longitudinally to ensure that the slurry fills the surrounding rock cracks of the entire section of the rear tunnel.

6. The double-shield TBM cross-line construction method in a geological fracture zone according to claim 1, characterized in that: In step 3, based on the geological structural fracture zone development data, when the TBM is excavating through rock with well-developed joints and fissures or a fault fracture zone, intelligent TBM excavation methods are used. A jam warning system is installed on the TBM. The jam warning system monitors torque changes and combines the TBM equipment propulsion parameters to select TBM excavation parameters, including: Step 31, tunneling is performed in an automatic torque control mode or a manual control mode; Step 32: When tunneling in the automatic torque control mode, the tunneling penetration is 15-30 mm, the torque value is 60-75% of the rated value, the cutterhead speed is 2-4 r / min, and the thrust is 40%-60% of the rated value, 5000-7000 kN. Step 33: When tunneling in manual control mode, the thrust is 50% to 70% of the rated value, 6000 to 8000 kN, the tunneling penetration is 10 to 20 mm, the torque is 50 to 60% of the rated value, and the variation range is less than or equal to 10%, and the cutterhead speed is 1 to 3 r / min; Step 34: During the excavation process, if it is found that the proportion of rocks with a diameter of 30 cm reaches more than 20%, the excavation speed is reduced, the penetration is within 5 mm, the torque variation range is within 10%, and the advancement speed is less than 60% of the preset value, so as to steadily cross the broken zone.

7. The double-shield TBM cross-line construction method in a geological fracture zone according to claim 1, characterized in that: The special structure segments are installed in the first tunnel in a timely manner as described in step 4. The grouting hole casings are embedded in the segments during prefabrication, including: Step 41: For the special segment structure, excluding the capping block, each segment is provided with four grouting holes in addition to the hoisting holes. The grouting hole casings are prefabricated simultaneously with the segment, and the circumferential spacing of the grouting holes is 1 / 3 to 1 / 2 of the segment width. Among them, the special segment structure is a segment with 40kg / m³ more reinforcement than the ordinary segment and 4 more grouting holes; Step 42: In the leading tunnel, special structural segments are used to perform lateral grouting pre-reinforcement treatment on the surrounding rock between the two tunnels and the cracks in the surrounding rock of the trailing tunnel; Step 43: When the two lines are switched, special segments are installed in the adjacent leading tunnel to resist deformation caused by the excavation thrust and the squeezing pressure of the horizontal support shoes during the excavation of the subsequent tunnel, ensure the forming quality of the leading tunnel, and resist deformation of the leading tunnel caused by the permanent dynamic load of train operation in the subsequent tunnel during the operation period.

8. The double-shield TBM cross-line construction method in a geological fracture zone according to claim 1, characterized in that: In step 5, a support system consisting of multiple trolleys is installed in the pilot tunnel. Each trolley is equipped with hydraulic support shoes to provide sufficient single-point support force, including: Step 51: The entire support system is composed of multiple trolleys. The trolley structural components include the trolley gantry, walking beam, support shoes, hydraulic system, and electronic control system. The material of the trolley components is not less than Q335, and the connecting bolts between components are not less than 10.9 grade. The welds are all groove welded and tested for flaw detection. The main beam of the walking beam is made of steel, and the remaining components are welded with 20 mm thick steel plates. Step 52: Each trolley consists of three horseshoe-shaped gantries. The distance between each gantries is the same as the width of the pipe segment. The inner diameter of the horseshoe-shaped gantries meets the clearance requirements for the slag train. The outer side is polygonal. Five hydraulic support shoes are installed on the outer edge of each gantries. Each support shoe provides a support force greater than 45 tons. A set of running wheels is installed under the walking beams of the front and rear gantries of each trolley. The middle gantries are equipped with adjustable screw top supports. Step 53: Install a self-locking hydraulic cylinder and a polyurethane steel box on each support shoe. The cylinder has a diameter of 150 mm and a stroke of 300 mm. A pressure sensor is also installed. The polyurethane steel box has a thickness of 200 mm and a width of 150 mm. Step 54: The support shoe is powered by two hydraulic pump stations with a flow rate greater than or equal to 10 L / min, and the system pressure is 25 MPa; Step 55 , the electronic control system is an integrated touch screen control panel, which controls the extension and retraction of each support shoe cylinder and simultaneously realizes the linkage of the extension and retraction of the entire group of cylinders.

9. The double-shield TBM cross-line construction method in a geological fracture zone according to claim 1, characterized in that: In the crossing and overlapping section described in step 6, a combination of automated and manual monitoring is used to monitor ground settlement, segment deformation, and trolley stress and deformation. When the monitored value reaches 70% to 100% of the control value, a graded warning is triggered, including: Step 61: Surface settlement monitoring points are arranged every 10 m along the axis, with a monitoring longitudinal section spacing of 20 m to 50 m. A total of 7 sections are arranged, with 9 points arranged transversely in each section, with a spacing of 3 m to 10 m. Step 62: The interval between the segment deformation monitoring points in the tunnel is 5 m, with 3 monitoring points in each section, 1 vault settlement monitoring point, and 1 set of convergence monitoring points. Step 63: The support trolley stress monitoring points are located at the head and tail of the preceding tunnel support reinforcement trolley. Two sections are arranged, and three measuring points are arranged on each section. They are located on the left and right sides and the top of the support trolley to automatically monitor radial forces. The stress measuring points use surface strain gauges welded to the support structure of the support trolley. The support trolley deformation measuring points are arranged synchronously with the support trolley stress monitoring point sections. Three measuring points are arranged on each section. They are located on the left and right sides and the top of the support trolley. Step 64: Annular stress monitoring points are arranged in sections of the tunnel segment structure simultaneously with the deformation sections of the support trolley. Two monitoring points are arranged on each section, located on both sides of the segment. The segment stress monitoring system moves forward with the support reinforcement trolley until the overlap section ends. The movable trolley support position is matched to the subsequent tunneling speed of the TBM. Step 65: The monitoring cycle begins with the installation of the support trolley. Each monitoring section monitoring cycle is repeated as the support trolley of the preceding tunnel advances forward until the TBM assembly ring of the succeeding tunnel leaves the overlapping parallel terminal mileage. Step 66: During the monitoring period, the ground settlement, segment settlement and convergence, and trolley deformation are monitored twice a day. The support trolley and segment stress monitoring uses automated real-time monitoring to collect data. Step 67: The surface settlement change rate is ±3 mm / d, and the cumulative value is ±30 mm; the clearance convergence change rate is ±3 mm / d, and the cumulative value is ±0.2%D, where D is the tunnel diameter; the structural crown sinking change rate is ±2 mm / d, and the cumulative value is ±20 mm; the trolley structure deformation control value is 10 mm; Step 68: When the monitored value reaches 70% of the control value, a yellow warning is issued; when it reaches 85% of the control value, an orange warning is issued; and when it reaches 100% of the control value, a red warning is issued.

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